Poets and blues singers long have waxed romantically about the way a woman moves...

Now, researchers are saying that the way a female moves may not be so good athletically. How female athletes jump, land and cut — or turn quickly — may be the reason that 50,000 female athletes tear a key knee ligament each year, a paper presented last month at the American Academy of Orthopaedic Surgeons suggests.

"We found that we could predict with about 90 percent accuracy who was going to have an ACL injury," said Tim Hewett, director of the Sports Medicine Biodynamics Center at the Cincinnati Children's Hospital. "We know the deficiencies; now we can start preparing them."

The findings are the latest step in a long trail of research into why female athletes are nearly eight times more likely to tear an ACL than their male counterparts. The frequency of ACL tears in women has long perplexed trainers, surgeons and researchers, with everything from hormones to muscle strength being pinpointed as the cause. And while some researchers have now isolated movement as a possible factor, they are struggling with how best to help female athletes prevent the injuries.

The anterior cruciate ligament, or ACL, is one of four elastic-type bands of tissue in the knee that help hold the joint in place. The ligaments also help transmit weight through the knee.

The injury requires surgery in which the doctor takes part of a nearby tendon to fashion a new ligament. It is kept in place with a metal nail and screw. The surgery costs between $18,000 and $30,000 and requires six months to a year to rehabilitate.

An ACL injury not only sidelines a school athlete, research suggests, but also can lead to depression and falling behind in school.

Mallory Springfield, a sophomore at Lassiter High School in Cobb County, did not become depressed after she tore her ACL last fall, but she did have to work hard to stay up with her studies. For weeks after her September surgery, she had an hour of physical therapy every day before school.

"It was tough staying awake at school," she said.

A striker on the Concorde Fire soccer club and also for her school team, Mallory tore her ACL after colliding with a goalie during a match in New York. She landed flat on her back, with her right knee twisted behind her.

"I knew right away that something bad was wrong," Mallory said last week. "I thought I broke my leg in half; I was hysterical."

As she lay on the field, she worried most about what most competitive athletes worry about when they are injured: missed playing time.

"I was thinking, 'please don't let it be serious,' " she said. "I wanted to play so bad."

The injury sidelined her for six months. She hopes to return to a scrimmage for the first time Wednesday.

Researchers originally thought the difference in risk of injury and number of ACL injuries in men and women came down to hormones. Men have more testosterone, which leads to bigger muscles. Researchers also implicated estrogen, which women have more of and which can lead to a loosening of connective tissue.

But then researchers noticed that young girls who had not yet hit puberty also were having more ACL injuries than young boys. Out went the hormone theory and in came the upper leg theory.

That one suggested that the difference was due to weaker upper leg muscles in female athletes. That comparative weakness made the knee joint loose, doctors thought, causing more stress on the ACL, which helps hold the knee in place.

So trainers stressed better conditioning for the females, and they strengthened their leg muscles. They still tore their ACLs.

"Most of the female athletes I've done this [procedure] on are very muscular," said Dr. John Xerogeanes, chief of sports medicine at Emory University and team orthopedist for Georgia Tech.

April Johnson, 20, a Tech forward, has torn an ACL twice within 18 months; first her left and then her right. The Macon native had never suffered an injury, not even a sprain.

That changed during a practice in the fall of her freshman year in 2002.

"Someone kind of bumped me on the side. I felt something shift in my knee," she remembered. She wasn't too worried because the pain was not unbearable. An MRI later found a torn left ACL; she missed all but five games of her freshman year.

On Feb. 25, she was running on a fast break. She jumped, landed and felt something grind in her right knee. This time, she knew what had happened, and she cried.

"I was just screaming, 'no, no, not again,' " she said. Xerogeanes operated on Johnson for the second time March 9. She is in physical therapy every day and doing well, she said.

Tech point guard Nina Barlin also has had two ACL tears. The injury was blamed for the Oklahoma Sooners' slide from national prominence last year; three players tore their ACL, including two on the same day.

With such highly conditioned athletes tearing their ACLs, researchers now are closely examining movement patterns, and they have seen what they consider some remarkable differences.

Dr. Bing Yu, director of the Center for Human Movement Science at the University of North Carolina at Chapel Hill, said girls' knees move more when they land, starting at about age 13. That makes their knees less stable.

Also, in separate studies, Yu, Hewett and others have found that female athletes tend not to bend their knees as they land, causing them to bear more weight than their male counterparts. The extra force causes stress to the body, particularly the ACL.

"If I hit the ground, the ground hits back," Hewett explained. "Girls let the ground hit harder, making the knee work like a ball and socket. In boys, it works like a hinge."

Hewett's study on how women athletes move also appeared to show that intense motion and strength training — 90 minutes, three times a week — can help prevent ACL tears. The program included retraining in jumping and landing as well as muscle strength training, and was conducted with 41 female soccer, volleyball and basketball players from Cincinnati high schools. The results also lead some to wonder whether female athletes as young as 8 should begin motion training.

Results from another study showed that training, albeit for a shorter time, did not result in fewer injuries. Ronald P. Pfeiffer, director of the Center for Orthopaedic and Biomechanics Research at Boise State University, looked at 1,439 female teens to see whether repetitive landing and jumping exercises 20 to 30 minutes, two to three times a week, lowered their injury rates.

Pfeiffer isn't optimistic that female athletes could devote 90 minutes to their workouts just for injury prevention.

While the latest study is promising, Xerogeanes said, prevention and treatment of ACL injury needs further study.

"There are still things we don't understand," Xerogeanes said. "Whoever figures this all out is going to be a very famous man."

I have to agree on everything I have suffered knee injuries too. Not to long a go I tried to run 10 kilometers and on the 6th KL. I started to feel a huge pain on the side of my right knee and I had to stop because of the tremendous pain. I went to the doctor and he told me that the ligaments were damaged and so on and bla bla bla. I just had to take a couple of pain killers and he put me to run inside a swimming pool for 20 minutes, and do some extensions and some other exercises and in a week I felt the difference. But I couldn’t climb for 2 weeks aaahhhhh I got very sad but I’m much better, but when I climb I still feel a small pain

i also enjoyed this article. i sprained my MCL earlier this year just with a stupid injury. knocked me out of climbing for 6 weeks, so it could have been worse. turns out the way i walk (knees not directly centred over my second toe like they're "supposed" to be) puts an extra strain on my MCL, and i had to do lots of physio to build up the supporting muscles. like my quads. now my quads have outgrown my harness leg loops, and i'm not too sure how i feel about that.

i also enjoyed this article. i sprained my MCL earlier this year just with a stupid injury. knocked me out of climbing for 6 weeks, so it could have been worse. turns out the way i walk (knees not directly centred over my second toe like they're "supposed" to be) puts an extra strain on my MCL, and i had to do lots of physio to build up the supporting muscles. like my quads. now my quads have outgrown my harness leg loops, and i'm not too sure how i feel about that.

I have the same problem with my knees...I toe-out and if i keep my feet perfectly straight forward, my knees point inward. I had major problems when I was in the army with stress fractures in my feet and cartilage damage to my knees (maybe it was my ACL, who knows? not the army, that's for sure). Anyway, only way to solve the problem was lifting heavy iron to get my quads strong. I'm virtually pain-free in my knees now, thanks to that.

that is a good article, thanks for sharing.... does anyone know anything regarding tendinitus of the quad? I got injuried on the job 2 wks ago and still feeling some pain, have seen the doctor, but am interested more on tendinitus especially how it can affect climbing.

That was an interesting article. I had heard about my female acquaintances tearing their ACLs, and I knew it was bad, but I had never known anything more about it. It's good information for someone injury prone like myself. I often find myself trying to "stick" the landing after falling off of a boulder problem - a habit from previous gymnastic days - but I really need to stop!

I am among the injured knee crew as well. I tore my ACL January of 2004. The statistics on knee injuries in women are so crazy. I've heard another theory that the heads of the femur and tibia are smaller and more rounded in women than in men, making the knee joint more likely to spread and buckle when landing or changing direction rapidly. I know this article negates the hormonal theories, but there are lots of studies that correlate knee injuries with the use of birth control pills as well. I had a lot of time to sit and read about ACL injuries during my recovery.

The most important thing I learned was: Keep your hamstrings strong! Muscle balance between your quads and hamstrings is so important and will help you prevent knee injuries and recover from them faster.